const digitsRE = /(\d{3})(?=\d)/g

export function currency(value, currency, decimals) { //格式化钱
	value = parseFloat(value)
	if (!isFinite(value) || (!value && value !== 0)) return ''
	currency = currency != null ? currency : '$'
	decimals = decimals != null ? decimals : 2
	var stringified = Math.abs(value).toFixed(decimals)
	var _int = decimals ?
		stringified.slice(0, -1 - decimals) :
		stringified
	var i = _int.length % 3
	var head = i > 0 ?
		(_int.slice(0, i) + (_int.length > 3 ? ',' : '')) :
		''
	var _float = decimals ?
		stringified.slice(-1 - decimals) :
		''
	var sign = value < 0 ? '-' : ''
	return sign + currency + head +
		_int.slice(i).replace(digitsRE, '$1,') +
		_float
}